Wireless Monitoring of Volatile Organic Compounds/Water Vapor/Gas Pressure/Temperature Using RF Transceiver

This paper describes the development and characterization of a wireless pressure monitoring system (WPMS) using an integrated radio frequency (RF) transceiver for applications such as monitoring of exerted vapor pressure variations of gases, volatile organic compounds (VOCs), and water vapor. Parametric sensing and environment detection using integrated approach are the key drivers for modern sensor technology. Our WPMS has an operating frequency band of 2.3152-2.6478 GHz. It has been developed using a pressure transducer, voltage-controlled oscillator, amplifier, and transmit/receive filtennas (filtering antennas). Transmitting antenna has been used for radiating RF signal (conditioned pressure information), while reflecting the undesired harmonics. Filtering antenna at the receiver side has been used to detect the desired RF signal, while filtering out the undesired signal. Experiments have been performed for monitoring a pressure variation of 0-50 kPa for a distance of 3 m from the transmitter. The pressure sensitivity of the system is 6.4 MHz/kPa with a good linearity response. Wireless temperature monitoring using our constructed RF sensor has also been demonstrated. The temperature sensitivity of wireless temperature monitoring system is about -662.2 kHz/°C between -55 °C and 130 °C. Calibration curve and polynomial fitting equations have been provided for evaluating pressure and temperature variations. The main advantages of this integrated system are integrated design, high-pressure/high-temperature sensitivity response, good linearity response, lower cost, less complexity, handheld, compact size, increased flexibility, and indigenous subsystems. The proposed system is suitable for wireless pressure/temperature monitoring applications in gas/oil industry, VOC industry, and steam industry.